extract_power_stable {WaverideR}

Extract power from a wavelet spectra by using a constant period/duration

Description

Extract spectral power from the wavelet using a constant period/duration and boundaries as selection criteria. The extraction of spectral is useful for cyclostratigraphic studies because the spectral power of an astronomical cycle is modulated by higher order astronomical cycles. The spectral power record from an astronomical cycle can thus be used as a proxy for amplitude modulating cycles. The spectral power is extracted from a wavelet spectra which was created using the analyze_wavelet function for a given, cycle, period_up and period_down

Usage

extract_power_stable(
  wavelet = NULL,
  cycle = NULL,
  period_up = 1.2,
  period_down = 0.8
)

Arguments

wavelet

Wavelet object created using the analyze_wavelet function.

cycle

Period of cycle for which the power will be extracted from the record.

period_up

Species the upper period of the to be extracted power Default=1.2.

period_down

specifies the lower period of the to be extracted power Default=0.8.

Value

Returns a matrix with 3 columns. The first column is depth/time. The second column is extracted power. The third column is extracted power/total power.

Author(s)

Code based on the reconstruct function of the 'WaveletComp' R package which is based on the wavelet 'MATLAB' code written by Christopher Torrence and Gibert P. Compo (1998). The functionality of this function is is inspired by the integratePower function of the 'astrochron' R package

References

Angi Roesch and Harald Schmidbauer (2018). WaveletComp: Computational Wavelet Analysis. R package version 1.1. https://CRAN.R-project.org/package=WaveletComp

Gouhier TC, Grinsted A, Simko V (2021). R package biwavelet: Conduct Univariate and Bivariate Wavelet Analyses. (Version 0.20.21), https://github.com/tgouhier/biwavelet

Torrence, C., and G. P. Compo. 1998. A Practical Guide to Wavelet Analysis. Bulletin of the American Meteorological Society 79:61-78. https://paos.colorado.edu/research/wavelets/bams_79_01_0061.pdf

Routines for astrochronologic testing, astronomical time scale construction, and time series analysis <doi:10.1016/j.earscirev.2018.11.015>

Examples

#Extract the spectral power of the 210 yr de Vries cycle from the Total Solar
#Irradiance data set of Steinhilber et al., (2012).

TSI_wt <-
 analyze_wavelet(
   data = TSI,
   dj = 1/200,
   lowerPeriod = 16,
   upperPeriod = 8192,
   verbose = FALSE,
   omega_nr = 6
 )
TSI_wt_pwr_de_Vries_cycle <-  extract_power_stable(
 wavelet = TSI_wt,
 cycle = 210,
 period_up = 1.2,
 period_down = 0.8
)